The present invention relates to electrical discharge machining, EDM, and more particularly to an arrangement of elements for laterally displacing one of the electrodes of an EDM machine in a plane perpendicular to the axis of feed of the electrode. The present invention relates generally to a mechanism which has come to be known as an orbiting mechanism for curvilinearly translating an electrode, in an EDM machine, in a transverse plane perpendicular to the longitudinal axis of feed of the electrode relative to the other electrode, one of the electrodes being a tool electrode and the other being the workpiece.
It is known to machine, by EDM, a workpiece electrode by means of a tool electrode by longitudinally feeding one of the electrodes relative to the other while simultaneously translating one of the electrodes in a plane perpendicular to the feed axis, and to provide means for displacing in the translation plane an eccentric member as a function of the relative longitudinal axial position of the electrodes with an amplitude proportional to the axial displacement of a shaft whose axis is parallel to the axis of feed. The amplitude, or amount of eccentricity, is caused to increase from a predetermined amount of eccentricity for a given relative position of one electrode relative to the other, the axial relative displacement of the shaft relative to the eccentric member being controlled such as to maintain predetermined electrical discharge machining conditions in the machining zone between the electrodes.
Such an arrangement of elements is disclosed, for example, in U.S. Pat. No. 3,539,754 and in the German Published Patent Application No. 2,238,698.
The present invention is an improvement of such apparatus and accomplishes the result of providing a simple and low-cost device while permitting to achieve the close tolerance which must be respected between the amplitude of the radial displacement and the amount of relative axial displacement of the electrodes.